The present invention generally pertains to thermal energy conversion, and is particularly directed to an improvement in energy conversion derived from temperature and pressure differentials that may be provided between high and low elevations.
Examples of prior art systems based upon this principle are described in U.S. Pat. No. 3,894,393 to Carlson for Power Generation Through Controlled Convection; (Aereoelectric Power Generation); U.S. Pat. No. 4,106,295 to Wood for Air Pressure Differential Energy System; and U.S. Pat. No. 4,143,516 to Long for Air-Water Power Generator.
In the system described in U.S. Pat. No. 4,106,295, a vertical conduit is provided for transporting a solution of a liquid in a gas from a low elevation to a high elevation, whereby the absolute pressure and temperature of the solution decrease and the solution rises in response to pressure differentials created by the decrease in average proportional density in the conduit. Water vapor is injected into the conduit to increase the created pressure differential. A heat exchanger is provided at the low elevation, high atmospheric pressure end of the conduit to warm the solution. A turbine is coupled to the heat exchanger and is impelled by the warmed solution to provide a useful form of energy. The heat exchanger may derive its heat from either a geothermal energy source or from a solar energy conversion system.
In the system described in U.S. Pat. No. 4,143,516, flow of a solution of a liquid in a gas in opposite directions through vertical conduits is accelerated by evaporation of heated liquid to decrease the density of the solution entering the lower inlet end of one of the conduits in an upflow direction. Separation of the liquid from the solution adjacent the upper outlet end of the upflow conduit further accelerates the flow. The flow is thermally induced by heat exchange in the downflow conduit. The liquid may be heated by fossil and non-fossil fuels as well as by natural heat sources such as geothermal or solar energy sources. The separated liquid is recycled into the supply of heated liquid. The kinetic energy of the upward flowing solution is converted by a turbine into a useful form of energy.